


Carte Blanche

by Bunsuu



Category: Transformers - All Media Types, Transformers Animated (2007)
Genre: Accidental Voyeurism, Dubious Consent, Exhibitionism, Extremely Dubious Consent, Forced Masturbation, Forced Prostitution, Forced Relationship, Gangbang, Humiliation, Master/Pet, Mutual Masturbation, Non-Consensual Touching, Orgasm Denial, Other, Public Humiliation, Sexual Coercion, Size Kink, Sticky Sexual Interfacing, Verbal Humiliation, Webcam/Video Chat Sex, Workplace Relationship, Workplace Sex
Language: English
Status: In-Progress
Published: 2015-01-07
Updated: 2016-08-21
Packaged: 2018-03-06 14:32:29
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 10
Words: 11,733
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3137831
Author URL: https://archiveofourown.org/users/Bunsuu/pseuds/Bunsuu
Summary: <blockquote class="userstuff">
              <p>Once someone is bound to their word, there's no turning back.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Prologue. I like cutting my work into shorter chapters as it makes it easier to read, I think. Thank you for reading!

To accomplish their dreams, one does anything in their power to obtain them. Some are dutiful and stubborn characters who will always believe the ends will justify the means; or rather, no matter how low they must bring themselves to go, no matter what burden they have to bear, when they get to make their dream a reality all of it would be worth it. All of the pain, the blood, and all of the sins would no longer have any value to them.

Sentinel Prime is one such dreamer. 

Today was a crucial day for Sentinel's dreams having any chance of becoming reality. To one day become Magnus was the blue bot's naive little fantasy, and to have a good chance of becoming Magnus, it is advisable to be the current one's right-servo bot. Obviously Sentinel had jumped at the chance to gain this position as soon as he was eligible. 

"I see... hm." Ultra Magnus sat at his desk, arms folded as he regarded the blue Elite Guardsmech in font of him stoically. They had just concluded going over his admission papers. Truthfully there really wasn't anything truly stellar about this mech, though he was above average in most categories, there wasn't anything that had set him apart from the other applicants.

Well, nothing that was anything to do with his capability as a soldier, at least.

The elder mech would have grinned had he not needed to remain rigid as he was: this was his favorite part of the whole process. He sent a ping from his data console to the door, which turned the doorframe's upper light from green, unlocked, to scarlet, which signified that it had been locked. He closed Sentinel's application and shut off the data pad, setting it aside gently. 

The young bot squirmed in his seat, trying to hide his nervousness. What was his commander going to say now? He had tried to be as charming, and obedient, as possible during what little time they had interacted with eachother. What effects that had on the older bot he couldn't say; the Magnus had remained curt and stone-faced the whole time!

Ultra Magnus looked the aspiring commander over, not bothering to hide how his gaze traveled up and down his entire frame in a somewhat questionable manner. The Prime had a broad upper body, with large shoulders equipped with shoulderpads which created an illusion of more mass than was actually there. His chin and jaw area was also much larger than on most mechs, but it didn't look out of place on him. However the bulk tapered down to a narrow waist and shapely legs and hips. It was a quite nice figure, in fact. Thighs thicker than most of the other mecha of his size, and hips that weren't too narrow but weren't too wide either. This was what kept Magnus' attention, rather than the accounts of his achievements as a cadet and as a Prime. 

Sentinel shifted about in his seat before the Magnus' desk, optics betraying his nervousness. Double checking the door was indeed locked, he tilted his head upwards to meet the younger bot's gaze. Gaining eye contact but Sentinel immediately looked away, the fidgeting increased doubly, and Magnus was now able to feel the tension in his field. Wetting his derma while Sentinel was looking away, Magnus cleared his intake curtly. The poor young bot startled and jolted upright in his seat, staring at his commander with wide optics.

"Yes, sir?" 

Really. This bot was too easy to read for his own good. Pretty soon he'll know that too, if he passes the 'special exam' to become his... direct subordinate. 

"Sentinel, you needn't be so formal."

The Magnus smiled benignly, raising his arms to rest his elbows on the slate-colored office desk. To anyone who wasn't a former Second-in-Command under Ultra Magnus, the smile would have looked innocent and radiant. To those that had served under the Magnus' heel as SiC, well, it made them shiver and cower. 

"Yes sir, sorry sir."

Good, he didn't need to train him to address him properly in non-official 'meetings' and drills. 

"There are... other things you must do to accomplish your duties as my sub commander than the basics we just have concluded discussing."

Sentinel nodded stiffly, determination and a little bit of apprehension flooded the EM field that now filled the entire room, to the Magnus' amusement. He tapped his fingers across the desk's surface, smile never fading from his faceplates. 

"Of course, I don't know whether or not you're capable of these duties yet," he hummed, "Perhaps you'd like to... prove yourself?"

Ultra Magnus narrowed his optics, something dangerous glimmering behind the cool blue that Sentinel couldn't put a finger on. However, he considered those words for a klik before nodding enthusiastically once more. Sentinel couldn't turn back now; this was his only feasible passageway to becoming Magnus, the only way he could... for Elita's memory. For her sake, he would do it.

"Good. Very good. Now, I want to make something clear to you so you don't do anything foolish after this last... test. What happens and what I say from this moment on will stay as business between me and you. Secondly you can back out of this test whenever you wish, but by not going through with it you will not be admitted to the position of Second in Command."

Magnus paused, watching how Sentinel prickled with fear but also with stubborn perseverance. Perfect.

"And, if you do try to speak about this to anyone, know that they won't believe you; and that I can accuse you of being a Decepticon spy and have you thrown into the stockades and nobody would bat an optic."

"What? Sir...?"

Sentinel swallowed, he didn't like the tone of that last bit. 

"Come here."


	2. Chapter 2

**Summary for the Chapter:**

> Bloop hello I am back with more self-indulgent smuts. I have SO many Sentinel drabbles to post... I'm at like 40 asdf

"Come here."

With his index servo he motioned the blue mech over, optics greedily roving across the glossy plating. Confused and a little alarmed, Sentinel made his way around the desk to stand in front of the Magnus, who had turned to the side and was oogling the codpiece a few feet away from his servos. He couldn't wait to dig in. But he was standing too far away! Pointing to the ground in front of him, his smile turned into a smirk.

"Stand right here."

"Uh... yes, sir."

Moving to the designated spot he waited for command, not quite sure about what he was going to be asked to do. At that moment, Ultra Magnus abruptly released his interface panel, spike instantly pressurizing to its' full girth and legnth. Sentinel startled, stepping back. Warning alarms blared in his helm. On the other hand, Ultra Magnus merely chuckled and spoke.

"I've been told my equipment is intimidating, though it's merely proportionate to my frame."

"Sir!! What are you doing?!"

Sentinel panicked on the spot, appalled by this shameless display by his superior.

"I told you, you have other duties as my second than to just sit around and look pretty. That is, unless you don't want the position," Sentinel's frame jerked, "if you do, then be a good bot and come back over bere."

He shifted, hesitating, balancing out the pros and cons speedily in his processor, staring at the thick girth with apprehension. There was no way that he could have ever expected this! But, he couldn't walk away now...

"Sentinel Prime, that was an order."

Once again a dangerous edge twisted that seemingly innocent statement into something a little more sinister, completely unnerving Sentinel. 

"Sentinel. Prime. Do you want this position or should I just dismiss you and reassign your post?" 

For Elita-One.

The Prime shook his head and moved back into position. Ultra Magnus smiled at him once again, unfolding his servos. Those servos then moved from his lap to caress Sentinel's sides in a quite suggestive manner. Heavy servos slid down to his hips and inward. Sentinel faught to keep from shaking, but when those servos reached inbetween his thighs he couldn't stop his thighs from closing by instinct. The elder mech chuckled at the timid display, using his stregnth to part those thighs himself with his trapped servos. 

One servo slid up his thigh to his panel, kneading at the blue metal lewdly. Magnus traced the seams and pawed at it lazily, a devilish grin on his faceplates. 

"Open up, sweetspark. Or I'll open it myself and keep it as payment." That was a joke, right?

Sentinel shuddered and complied regardless. One servo slipped down to his valve and the other teased his spike housing. Biting his derma, Sentinel shook more as the folds of his valve were stroked and parted, already a lirrle bit lubricated. The servos were skilled, Sentinel's spike was halfway pressurized in no time at all and his valve was dripping with lubricant after his superior had played with his exterior node. Magnus parted the valve's folds with two digits, slipping the third in and making Sentinel squirm.

"Sir!" But the cry went unanswered, the digit stroking at walls of his valve and pressing in deeper and deeper until the tip of his finger brushed the filmy surface of Sentinel's seal.

The Magnus' engine revved upon finding it, and the Prime yelped at the strange and foreign sensations it gave him. A wicked smile crept up onto the old Autobot's faceplates as he stood up from his chair, removing his hand from the array. At a loss for words Sentinel cowered in place as he gazed upon the indimidatingly large figure in front of him. Ultra Magnus' servos shot out and picked up the navy blue and orange frame easily, prompting a sharp cry of alarm from his vocalizer. Kicking his chair back away from the table Magnus sat down Sentinel right in front of the desk and wasted no time in shoving the young Autobot onto it chestplates-first. Now, Sentinel's frame was bent over the desk close to a 90 degree angle, exposing his aft and array to the lecherous old mech's mercy.

When Sentinel tried to get up a servo on his back held him down on the top of the desk, effectively stopping his attempt to escape Magnus' clutches. A large thigh wedged inbetween his own, spreading his legs apart. Sentinel could hear Ultra Magnus' rumbling engines humming behind him. The commander moved his thigh in a manner which was forcing Sentinel's valve to grind against it, smearing the lubricant from the port all over the black and silver surface of his leg. 

"Do not move." 

The Magnus smirked, pulling his chair back over to him with his pede and sat down facing his subordinate's equipment. 

Two of the Magnus' fingers were roughly shoved into his virgin entrance at once this time, the young Autobot mewling pitifully at the different angle. He struggled not to writhe or try to escape his commander, however tempted he was. The two digits dove deeper into Sentinel's valve with avid intent. Not knowing what Ultra Magnus was planning to do wreaked havoc upon his already-stressed nerves. Sentinel mewled pitifully as the tips of the elder bot's fingers prodded at his seal, stroking it and playing with it while being careful not to pop it. 

"This," The Magnus purposely made a small puncture hole around the upper rim, "belongs to me now." 

Ultra Magnus carefully poked more at the outer edges of the seal, enjoying how his soon-to be-second-in-command jerked with pain each time. Once he completed the entire circle he held it between his index and middle fingers, gently removing the servo and thus pulling out the gossamer film which was slick with energon and lubricant. His free hand returned to the bared valve, stroking the outer folds again as Magnus gently raised the seal closer to his face, leering at the form upon his desk which still trembled from the stings of his newly-popped seal.

Meanwhile, Sentinel whimpered and squirmed in pain. Frag, he had never wanted to lose that seal...! He felt a little dirty, the urge to go scrub his plating clean almost unbearable. Sadly, Sentinel doubted the Magnus was going to tolerate him trying to escape very well. After a few kliks of caresses on his (somehow) still lubricating valve the Prime was tugged over, forced to roll onto his back. Upon onlining his optics Sentinel was greeted with the sight of Ultra Magnus looming over his prone frame, licking at Sentinel's seal between his fingers. 

The lecherous old Autobot smiled darkly as Sentinel Prime shivered, bright turquoise optics wide with nervousness fixated on his own dim cerulean pair. Finally, all of the lubricant and energon had been cleaned off of the diaphanous plastic. Magnus subspaced it while lapping up the mess of fluids around his derma absentmindedly. 

"Sir?" Sentinel squeaked, eying the broad mech mistrustfully. 

"Yes, Sentinel Prime?" Ultra Magnus' servo returned to his valve, digging three digits into the opening harshly which drew a high-pitched keen from the Prime's intake.

Those fingers thrust into the still-sore valve at a nearly violent pace over and over again, haphazardly scissoring and stretching the mesh walls on the withdrawal. Pain lanced up his neural net but it strangely melted into an intoxicating sensation that was closer to heady pleasure than anything else. Ultra Magnus exhaled, his fans clicking on as he palmed his spike. He couldn't wait to bury himself into the soaking wet little opening which clenched hard around his fingers. 

In fact, he truly couldn't wait. Magnus removed his servo and instead grabbed the smaller Autobot's left thigh, pulling it up and away from his frame, sliding between the parted legs hurriedly. 

"Sir-! Wait, please-!" 

"Hmmm, no." 

Guiding his spike to the dripping entrance and pressing the tip to it lewdly, Ultra Magnus leered down at the shaking navy blue frame. Waiting just a klik longer to revel in the pure fear upon his subordinate's faceplates. Several kliks passed before his grin turned to a cruel smirk and he slammed his hips forward. Sentinel screamed, his pedes kicking out reflexively.

Oh, frag. He was going to be keeping this recruit on a leash for a long time. Magnus wanted to make more screams to come from that pretty little intake; to listen to each sobbing keen as he rutted into this untouched and tight valve of his. 

The elder Autobot immediately set a punishing pace heedless of the pain Sentinel was likely feeling. 

"Oh Primus, that's-!" Sentinel wailed, coolant welling up at the corners of his optics. 

To his absolute shame, the Prime's valve kept lubricating even as energon dripped from around where the large spike had tore his valve lining. However, the amount of lubricant far surpassed the energon. As if that made him feel any better. All he could do was moan and cry as he was fragged by his commander on a desk with the mech's spike; Sentinel Prime had never felt more dirty than he did now. 

A familiar sensation of a spring coiling within his abdomen alerted Sentinel to the fact that he was going to overload soon. He couldn't help but sob as the Magnus sped up, placing one of those monstrous servos over his neck cabling and holding Sentinel down. The spring became tighter and tighter until it snapped, his hoarse vocalizer's howl of completion filling the office and a rush of lubricant burst from his valve, which reflexively clenched down upon the cord inside. 

With one more snap of his hips Ultra Magnus grunted and buried himself entirely into the smaller frame, his overload triggered by Sentinel's. Because the girth occupied most of the port, Magnus' transfluid filled up the valve to its utmost and then some, the excess messily overflowed around his spike and created a puddle of transfluid and lubricant on the tabletop and floor.

Almost immediately, the commander pulled out and cleaned his spike off with a rag that he kept in his subspace in a single elegant motion. 

"Well, Sentinel Prime. I look forward to having you under my command. Report back in my office tomorrow for orientation. And also," Ultra Magnus smiled again, "I will also teach you some of your other duties."

Sentinel could only weakly mewl in response, frame still reeling from his first valve overload, the Magnus' transfluid and his own lubricants leaking from his bleeding port. 

Primus, what had he just gotten himself into?!

**Notes for the Chapter:**

> Thanks for reading!


	3. Chapter 3

**Summary for the Chapter:**

> Short, but sweet, maybe?

Sentinel barely managed to clean himself up and drive back to his hab suite. Transforming was an actual pain with the soreness in his valve. Once home, he immediately stomped into the washrack and turned it on full-blast, sanitizing every inch of his frame to try and dislodge the feeling of being... debauched? Plundered? Something like that, anyway. Recharge soon called the Prime to limp back to his berth where he fell into recharge before he was properly laid down. 

 

The sound of his internal alarm awakened him the next cycle from a dreamless recharge sprawled haphazardly over his berth. A dull ache in his valve caused confusion for a klik until he remembered the events of the last dark cycle. Sentinel grimaced, feeling almost sick to his stomach not because he had been coerced into interfacing, but rather, that he lost his valve seal. Getting up and grabbing his morning rations from his dispenser, Sentinel chugged the fuel down as he normally did, stopping in front of his full-legnth mirror to ascertain his paint job was sufficiently glossed and pristine. 

Taking a deep vent, he pulled himself away from his reflection and exited the hab suite, mentally preparing himself to pretend the last cycle had never happened. Or, some aspects of it anyway. There was little he could do about this situation other than make a curteous run for it every time he was in a room alone with his commander. 

Sentinel wasn't looking forward to those 'other duties'. 

Fortress Maximus was easy to navigate, and as was ordered he reported to the Magnus' office on time. Upon entering the office itself, Sentinel noted grimly that he was the only other occupant of the office besides Ultra Magnus. 

"Good morning, Sentinel Prime." 

The strait-laced expression that the Magnus usually sported had always unnerved the Prime, but now it instilled a whole new anxiety in Sentinel's meta. But, Ultra Magnus looked the same as he always had for as long Sentinel has been online. Though he wasn't sure what he expected to change about him, honestly. It was as if nothing had happened just a cycle ago. Sentinel wasn't sure if he should be glad about this or even more wary of his superior. 

In fact, Ultra Magnus debriefed him about his duties for this solar cycle, which consisted of archiving summaries and a copy of reports from all over Autobot territory. Not hard at all, he mused. At least he wasn't in a combat position! Once dismissed he was waved off to his own office, which was close to the Magnus' office suite, with a pile of data pads cradled in his arms. His was decidedly smaller but Sentinel didn't mind, really. He sat down to get to work as soon as he was inside, sparing little regard for the office furnishings themselves. There would be time to fuss about decorating later. 

So, he worked. Reading report after report, summarizing the main topics of each on an official data-pad and making a copy of each before storing the original in a secure container which automatically locked itself each time it closed. The stack of data-pads steadily decreased as the megacycles passed. By the time he had finished, he wasn't tired but rather bored. The newly finished reports were to be returned to Ultra Magnus so he could sign off on them; this required him to go back into his commander's office. 

Which made his tank churn in uncertainty. How was he supposed to do this? Sentinel could barely keep himself from dropping the data pads all over the floor because of his shaky servos. There was little chance that he'd be able to stop doing so in the 'lair of the beast'. Still, he would complete his assigned task as he needed to make a good impression upon the Magnus. Reports in his arms, Sentinel exited the office and walked the short distance between their doors. 

His spark whirled in its chamber as he stared up at the forboding steel doors labeled 'MAGNUS' in dark printing. Venting hard, he reached out with one servo to touch the query button on the flatscreen security console next to the door. A klik later, the doors slid open to reveal Ultra Magnus sitting at his desk. Various data pads were strewn across the desktop, but not in a disorderly manner. There simply were a lot of them. 

"Come in, Sentinel Prime." Apparently Magnus had caught him gawking. 

Sentinel jumped and shuffled into the room, the door shutting (and locking, per Magnus' remote command) behind him. 

"Place those in the box labeled 'in'," Ultra Magnus tapped a box on the left side of his desk, "then sit down. We need to discuss some of your...tasks."

That smile crept up onto his faceplates as he spoke, Sentinel's tanks lurching at the memory of the smirk. 

The Prime quickly did as he was told, dropping the data pads in the office tray and plopping down into the plush chair. His frame seemed to sink into it, optics turned downward towards the floor and servos in tight fists on his lap. 

"Yes, Sentinel, I know that the floor is quite lovely, but you aren't being as subtle as you think you are."

Sentinel startled, a jumbled apology following after the Prime regained his wits. Looking up, Sentinel found the Magnus once again watching him with an intensity that sent shivers down his spinal struts. Ultra Magnus motioned him over, pointing to the ground next to his seat; the same place that he had ordered Sentinel to yesterday. Oh, slag, here we go again.

**Notes for the Chapter:**

> Thanks for reading! Almost done w/ 4.


	4. Chapter 4

Pushing out of the chair and stifly walking to where he had been ordered to go, Sentinel faught to keep from cowering in fear. To be perfectly honest, he didn't want to get fragged again! His commander turned towards him like he did yesterday, but, instead of ordering his subordinate's panel open, a large servo slid around Sentimel's hip and pulled him forward onto his lap. Their chests bumped together with a low 'clang', the smaller Autobot's legs folded on either side of Ultra Magnus' own.

"Sentinel, how do you like your new post?" The Magnus asked conversationally, even as the servo on Sentinel's hip trailed further around the frame and began to grope at Sentinel's aft forcefully.

"I do like it, sir..."

"That's good; though you still have a lot to learn to fufill your duties correctly. So many things I must teach you..."

The Magnus' servo on his aft dipped lower, stroking at the shivering mech's panel hungrily. Large fingers deftly teased the seams with practiced ease. It was embarrassing, but Sentinel could feel his panel heat up under the commander's ministrations. Ultra Magnus' other servo laid upon his thigh, sliding up and up until it came to his headlights. Digits probed exploringly at the seams, thumb swiping over his bumper playfully. The Prime shivered anxiously, bracing his servos on the broad indigo chest plates in front of him.

The elder Autobot's helm dipped down to nibble and suckle on Sentinel's neck, lavishing the surface with small dents. By instinct, Sentinel moaned and craned his neck for the Magnus to have better access to his outer intake tubing. Even though the denta stung each time they scraped over his plating, Sentinel found himself pushing his plating towards the Magnus' intake eagerly. The powerful engines pressed against his own rumbled in amusement, and the Prime's fans clicked on immediately after of their own volition as if they were answering.

Ultra Magnus pulled away from the neck cabling to kiss Sentinel, glossa slipping between the lax derma and exploring. Unconsciously, Sentinel's legs widened and he bowed his back a bit more, pressing his heated codpiece into the large servos stroking his panel. Meanwhile their glossas lazily wrestled and twisted together, tasting eachother in a heady dance.

_'Click'_

Embarrassingly enough, his panel opened by itself. Ultra Magnus drew back, the worrysome smile gracing his faceplates. Sentinel already knew that he was going to hate that expression, and it was his first official day on the job. Unsubspacing a small object, Magnus dug two fingers into the (shamefully) lubricating valve with it between both digits. The object was let go of deep within his valve, Ultra Magnus pulling the fingers out swiftly.

"Close your panel."

Though the Prime was clearly confused, he did so anyway.

"Good 'bot. Now, below my desk."

Wait. Below the what?! Sentinel blinked in shock, processor taking a moment to understand. Once it clicked, he scrambled down, onto the floor and beneath the desk. It was oddly roomy, with enough height to be able to sit upright without the risk of hitting his helm, and wide enough that Sentinel's legs didn't hit either of the drawers. But what was he supposed to do down here? Magnus pulled the chair in and patted Sentinel's helm lightly, blue optics still oogling his subordinate's frame lecherously.

"Sir...?" Sentinel squeaked, his nerves feeling like icicles prickling his neural net.

"Sentinel, have you ever used your intake on someone's hardware before?"

The Prime's tanks rolled. What he was going to be doing under the desk stark before him.

"No, sir, I... haven't."

"I see," the Magnus' grin widened. "So I will be the first bot to get to use your intake. Perhaps I'll be gentle on your intake, for today..."

As Ultra Magnus trailed off his panel snapped open, his thick legnth pressurizing immediately. It was certainly... larger than he remembered. Sentinel froze up, pushing himself away from the girth until his back plates hit the front of the desk. Expecting this reaction, Magnus only chuckled and reached under the desk, cupping Sentinel's faceplates and yanking him closer. The Prime yelped as he was moved to a position where the spike's head rubbed against his cheek and chin plates inadvertantly.

"Be a good bot and open up, or do I need to punish you for disobeying orders already?" The Magnus' voice was playful but Sentinel could detect a certain degree of malicious amusement in those words that were a clear warning that he had better do as he was told.

In the end, he really had no choice but to obey.


	5. Chapter 5

**Summary for the Chapter:**

> Learning how to please the Magnus, part one of many.

Taking a deep vent, Sentinel leaned forward and timidly lapped the head once with his glossa. The taste was strong, but not bad-tasting. With a shiver, the Autobot continued to lick at Magnus' spike, hoping he was doing a good job as to not invoke punishment.

"Hum. You really haven't done this before. Don't just lick at my spike like that, I want to feel your derma and glossa on me... for now, at least."

Another shiver passed through Sentinel's form, but he bit back whatever unpleasant emotion was bubbling within his intake and pressed his derma to the side of the cord experimentally. Magnus' servo was petting the top of the Prime's helm as he watched his subordinate work out how to please the elder mech on his own. It was cute, how demure and unsure Sentinel looked as the Autobot licked and suckled at his spike, staring at it suspiciously. Normally he would have just ordered the bot to open his intake to frag it, but, something about the way Sentinel was so obedient in trying to please him was intoxicating. 

Some prefluid leaked from the cord when Sentinel passed over it again, smearing the pale purplish-white fluid across his derma and cheekplates. Predictably, he squeaked in surprise and pulled back only to be grabbed and yanked forward again by Ultra Magnus. Cupping the side of his faceplates, the Magnus eyed the smeared fluid on Sentinel with a perverse glint in his optics. 

"You look good like this. Very good, even..." Magnus slid his thumb over the trail of prefluid, pushing all of the excess prefluid with it as he followed the trail to Sentinel's derma. 

He pressed on them gently, indicating he wanted access. Of course, Sentinel's derma quivered for a klik before hesitantly parting. The digit immediately slid in, most of the prefluid with it as it entered the warmth of Sentinel's intake. He pressed his thumb against the glossa and rubbed it gingerly to give Sentinel a good taste of his Magnus' fluid; it twitched against the thumb, Sentinel grousing at the strong taste. 

Then it pressed fully inside, making Sentinel gag a little from its' size. Oral lubricant escaped the corners of his derma and rolled down the sides of Sentinel's chin. Chuckling, Magnus pulled his thumb halfway out of the port before sliding it inside again. 

"This is what you're going to do with my spike, Sentinel," The spike poked at Sentinel's cheekplating playfully. "Although you'll be using your glossa. I also expect you to clean up every last bit of my transfluid with it, is that understood?"

Slag.

The Prime once again faught back a wave of hesitation and nodded jerkily. If he didn't do as he was told, his Magnus would probably go through with the earlier threat of punishment. That was something Sentinel wasn't keen on experiencing.

"Good. Now, before you start there are some rules we must go over. First, your servos will rest here," Magnus retrieved his servo from Sentinel's intake and grabbed one of his subordinate's and placed it upon his thigh, doing the same with the other. "And they will not move from here; if they do you will be disciplined. Secondly, before we begin I will show you the pace that I enjoy. You will maintain that pace until I overload. Thirdly, when I do overload, you are to lean forward to take the entirety of my spike into your intake to swallow all of the transfluid from it. Do not pull back until it's all swallowed, or you'll be licking it up from the floor before you're punished. Next, you are not to bite, but I think I won't have to worry about that with you, hmm?" 

He paused, leering at Sentinel, who merely stared up at him with a frown that the Prime was trying to hide. Wrapping his servo around the twin audial fins on the left side, Magnus pulled Sentinel forward until the spike's tip rested against the ashen derma. Sentinel shuddered and squirmed a bit within the elder bot's hold, optics trained on the girth that was supposed to be able to fit into his intake. He was nervous, but that was becoming the new norm, it seemed. 

"Oh, one more thing," Ultra Magnus' smile was brilliant as he spoke. "You are not to make any noise whatsoever, understood?"

"Yes, sir..." Though Sentinel couldn't imagine why he would make any noise. 

The servo on his audial slid to the top of his helm and back a little ways, pushing him down in the direction of the cord prodding at his derma. Sentinel's intake opened hesitatingly, and Magnus wasted little time before sliding the first bit of it into his subordinate. About the head and two inches were inside, resting on Sentinel's glossa. Its' taste was stronger like this, making the Prime grimace from the flavor. Spotting Sentinel's expression, Magnus laughed good-naturedly and patted the dark blue helm. 

Then, it was pressing down again, more of the girth being slid into Sentinel's intake. It poked at the intake tubing insistently, forcing him to stomp out the reflex of purging for the sake of obeying orders. 

"Relax, you're very wound up." The servo on his helm paused for a moment, petting between the bittersweet-colored stripes soothingly. 

Primus, he tried to. Somehow, it worked, if only fractionally loosening his intake tubing. Magnus pushed down again, managing to slide 3/4ths of the way in before it started hurting again. This time, though, Magnus didn't stop pushing. Sentinel shuttered his optics and tried his best to work the rest of it in as he leant forward. A few moments later, his derma brushed some sort of object in front of his helm. What...?

Onlining his optics he was met with the top of Magnus' spike housing. Surprised, he mewled around the spike in his mouth. 

"I said no noise, but, I'll be generous because this is your first time." Ultra Magnus huffed mirthfully, his spike certainly enjoying Sentinel's snug and quite warm intake. 

He pulled Sentinel back at a slow pace until only a half remained in the Prime's intake before pulling him forward again. They continued going back and forth until Sentinel was able to emulate it on his own. 

"Good, but you need to use your glossa. Also," He unsubspaced another small object with a grin. "Remember; no noise." Magnus flipped a switch on the side of the small purple orb, and whatever had been put into his valve a breem ago began to buzz. 

Sentinel jumped, managing to stop himself from yelping at the last moment. 

Someone pinged at the door, and Ultra Magnus winked at him.

"The rules still apply, Sentinel Prime."

**Notes for the Chapter:**

> Yo. Thanks for reading!


	6. Chapter 6

**Summary for the Chapter:**

> Yummy? Maybe. Ask Sentinel.

Panic raced through Sentinel's processor even as his hips squirmed from side to side due to the new onslaught of the vibrations from the object in his port. The doors slid open and the newcomer's pedefalls were heavy as they entered at a leisurely pace. Greetings were exchanged, and the stranger had apparently sat down on the chair he had occupied mere breems ago from the familiar sound of the cushions on it. What did Ultra Magnus think he was doing?! Well, it certainly seemed as though he knew what he was doing, but...

"Give your report whenever you are ready, Circuitbreaker." 

"Yessir!"

Magnus' pede nudged Sentinel's leg impatiently, his meaning crystal clear. Hastily, the Prime took 3/4ths of the spike back into his intake, working his glossa over the cord desperately. But soon his audial was grabbed and tugged forward, towards Ultra Magnus' hips. Grimacing, Sentinel shuttered his optics and forced himself to go down to the base, intake tubes uncomfortable and mildly burning due to the stretch. The girth was so huge; how had his valve ever taken this all the way inside on its' first time?!

Above him, Sentinel could hear the bot named Circuitbreaker give his report about something or another. Focusing on that, Sentinel bobbed his helm up and down on the commander's spike. The vibrator in his port felt shamefully good; Magnus had put it inside so deep that it was nestled against his back walls. Moving his hips resulted in it rubbing against a new cluster of nodes, which only made it harder to be silent. His glossa wrapped around the thick cord as well as it could, lapping at the shaft as if it were some sort of extremely large energon treat. 

To his surprise, eventually one of Magnus' servos reached down and placed itself heavily upon the back of Sentinel's helm and pulled him forward and pushed him back at an inconstant rate. The spike began to gently twitch in his intake and viscous prefluid slid down his tubing which had leaked from the very tip. It tasted strong on his glossa, not too sweet and not too sour; but definitely strong. Letting his commander control his movements, Sentinel relaxed and shivered as he felt his lubricants begin to soak through the seams of his panel. His intake still burnt, but he was getting used to it as time went on. Meanwhile, the servos resting upon Magnus' thighs trembled against the silver and black plating. More beads of lubricant began to escape his leaking panel, he could feel them as they rolled down his thighs slowly.

"What a good 'bot you are, Sentinel." Magnus' voice made Sentinel's field bristle in fear that quickly was found to be unnecessary, their visitor had left, apparently; it was near-silent again.

Sentinel mewled unenthusiastically around the spike in response, looking up at the older Autobot with dimmed optics. 

"Hmmm, I doubt you would be able to handle me overloading inside of your intake, considering you've never used your intake on anyone else before." Ultra Magnus hummed as he kept up the erratic pace. Seriously, this old mech had uncanny amounts of self-control; at this point Sentinel would be shaking and mostly failing at keeping his hips from ramming into the hot and moist bliss wrapped around his spike.

If he wasn't going to overload in his intake, then where...? Sentinel was abruptly pulled off of Magnus' spike by both of the commander's servos. 

"You've been so good today, my pet. I think you deserve a little... hmm... mercy. Sentinel," the Prime looked up at the Magnus with hazy cerulean optics. "Use your servos."

Mindlessly, he obeyed and wrapped them around his commander's spike. Moving his servos at a decent pace was difficult because of the distraction currently sitting in his valve, but he managed. He timidly glanced up at Magnus' faceplates, but offlined his optics when he saw his Magnus' familliar smirk that definitely put him on edge.

"Now, that certainly won't do. Online your optics," Magnus tapped a finger against the Prime's helm warningly; Sentinel's response was immediate and he turned them back on, focusing on watching his servos slide back and forth over the girth he was at optic-level with. "Look at me."

With bleary optics, Sentinel met his commander's gaze. His cheekplates were flushed with energon, the optic-contact making Sentinel feel even more embarrassed than when he had been servicing his Magnus under the desk while another 'bot, unaware, gave his report. Ultra Magnus' optics were brighter than usual, signalling his charge's intensity. 

"Open your intake... just a little." An odd command, but Sentinel did so anyways.

Suddenly, the Magnus grunted and his grip on Sentinel's helm became almost painfully tight. The Prime only had a klik to ponder the reason for this change until the first spurts of transfluid landed on his faceplates, making him sputter in surprise. Reflex kicked in and he tried to pull away only to be stopped by his Magnus' firm grip holding his helm in place, making Sentinel squirm as his faceplates became thoroughly covered in Magnus' transfluid. He was held there even after Ultra Magnus was done, absolutely humiliated. A deep chuckle resonated from above him as Sentinel grimaced from the strange feeling of the transfluid sliding down his chin and neck cabling. Teasingly, Magnus leaned down and kissed the top of his helm. 

"S-Sir!!" Sentinel squeaked, trying to sound offended or disgusted, though it came out like a pitiful mewl. 

"Yes, Sentinel Prime?" To Sentinel's astonishment, Magnus slipped his servos further down and picked Sentinel up with a peck on his derma. 

He was quite lazily plopped down on Magnus' lap, and the broad cheshire grin on the commander's faceplates was as playfully depraved as he had seen it every time. But there was no time to respond, as he was pulled forward and into a deep (and somehow, still hungry) kiss. Magnus found the feeling of his fluids on Sentinel's faceplates to be quite invigorating; the remnants of his spike and prefluid on Sentinel's glossa only added to it. Fingertips trailed down the legnth of the Prime's inner thighs and began to rub at the leaking seams of his panel. 

"It seems that you're running a little hot, aren't you?"

Sentinel moaned as his Magnus stroked his heated panel, sobbing when it opened if its' own volition.

"Relax, just let me take care of you, my pet."

**Notes for the Chapter:**

> As usual, thanks for reading!


	7. Chapter 7

**Summary for the Chapter:**

> Bloop this chapter took awhile because I changed its' plot twice. At least the next... 12 chapters are outlined so they'll be less arbitary!

A single digit traced the outer edge of Sentinel's valve before another joined it as they stroked over the center from bottom to top. They slid back down to rub at the folds teasingly, then parting them wide open as Magnus reclined in his chair. The Prime was tugged forward to rest upon the older mech's warm chestplates with his helm tucked under Magnus' chin. Against Sentinel's frame, the broad expanse of Ultra Magnus' chest felt soothing, the warmth alongside the gentle rumbling of his engines helping Sentinel along in practically melting into his commander's touches. Magnus felt his servo becoming slicked with the lubricant that gushed from the port hovering above his own array, making a mess of his lower half. His charge came back roaring almost immediately, though he didn't want to just throw Sentinel down on his desk or floor and have his way with the Prime this cycle; it was still mid-day and there was plenty of time to keep Sentinel 'occupied' with 'helping' his Magnus before their shifts ended for the day. 

Besides, Magnus had no other appointments, just reading written reports and signing off on their content. Kissing the top of Sentinel's helm, he moved his servo back up towards the top of the valve and playfully prodded at the exterior node with his finger. The response was instantaneous; Sentinel's hips bucked and he cried out, muffled by his commander's chestplates. Chuckling, Magnus softly pressed two digits to Sentinel's exterior node and gently rolled it between them. Again, the Prime's hips bucked, though, this time they jerked harder and shook against his ministrations as Sentinel keened desperately into his shoulder. Feeling merciful, Magnus decided to stop teasing and move on, even though part of him wanted to tease Sentinel until he was a begging puddle of desperate Autobot. After giving the exterior node one more playful nudge, the fingers slid back to the port's opening and circled slowly, making Sentinel shiver against Magnus' frame. 

This time, two fingers entered him at once. The Prime gasped and clung to the warm plating beneath him tightly as he felt his commander's fingers slide as deep as they could inside of his valve. Beneath him, Sentinel felt Magnus' spike jut heavily across his aft as Magnus stroked the slick walls of his port. Scissoring wide, the Autobot commander eased a third finger inside with the other two and hooked his fingers, rubbing over the node-lined mesh and making Sentinel keen desperately into his shoulder from the sudden onslaught of pleasure sparking through the Prime's neural recievers. Lubricant flowed freely from the ashen folds of Sentinel's valve and onto the shaft of Ultra Magnus's spike, which stiffened further against Sentinel's aft. Even though Magnus increasingly wanted to plunder the young Autobot's eager little valve with his spike, the commander drew out the process of stretching and exploring Sentinel's valve, reveling in the wet and fluttery heat that clenched around his fingers so very greedily. Sentinel, meanwhile, was shaking and whimpering into Magnus' neckplates, trying to muffle his embarrassing cries. 

Both fingers were withdrawn from Sentinel's port, a pitiful keen from the Prime following directly afterwards. Magnus aligned his spike with the opening and grabbed Sentinel by the back of his neck cabling to pull him back so that he could watch the Prime's reaction as Magnus lowered him onto his cord. 

"Sir..." Sentinel muttered; his vocalizer glitched as he hiccuped and moaned as the spike's ridges lit up almost every sensory node in the compact space.

Like last time, the port fluttered around Magnus, yet unlike last time, no pained keen left Sentinel's vocalizer. Fully seated on the cord, Sentinel looked down at where his valve folds were stretched wide to admit the older mech's hardware with dimmed optics and his derma parted ever so slightly. Streaks of transfluid clung to his flushed faceplates messily, though Sentinel seemed unaware of it. Which was good, the Magnus mused, he quite enjoyed the sight of Sentinel's faceplates covered in fluid... in fact, it was absolutely enticing. Lifting Sentinel up, Ultra Magnus stole a kiss from the slick derma before dropping Sentinel as he thrust upwards into the slick wet heat of his sub-commander's port.

"Sir--!" Sparks danced across the Prime's vision as his neural net lit up with a carnal pleasure that still was quite foreign to his processor. 

Both of Sentinel's servos clung to Magnus' chestplates as the action was repeated over and over again at a steady pace. Overload came quickly for him, the angle brushing over the blue and orange Autobot's ceiling node with precise accuracy. Magnus pulled Sentinel's frame flush against his chestplates, one servo pressing the Prime's hips down roughly. Catching an audial fin between his derma, Ultra Magnus bucked up into Sentinel's port with force; drawing a high-pitched keen from the younger bot. 

"Si-r...! Gh-," another thrust cut off Sentinel's mewl. "Sl... sla-ag!" 

Denta grazing the audial fin with indulgent laps of his glossa, Ultra Magnus reached between their frames and teased the weeping spike laying on top of his abdominal plating before setting a brutal, almost violent pace. Sentinel practically shrieked as he held onto Magnus' chassis for dear life. All of the nodes in his port were practically buzzing with intense and blissful stimulation; he felt as though his neural net was on fire or melting, wiping any semblance of coherent thoughts from the Prime's processor. Then Magnus bit down on the captured audial fin, and somehow the pain sent him over the edge and into the most powerful overload he'd ever experienced. 

Helm spinning, Sentinel groggily realized that his release had triggered Magnus' own. He could intimately feel the viscous fluid rush into his port and coat the fluttery walls. Magnus' frame was close enough that Sentinel could feel the sated rumbling of the aged engines beneath the broad expanse of his chestplates. Once he had completely finished overloading, Ultra Magnus pulled Sentinel into a demanding kiss that was sleepily returned by the younger Autobot. As it was, they were both quite... covered in fluids. Perhaps he should make Sentinel clean them up...? Though that would likely result in revving up his libido again. Besides, Sentinel was falling into recharge already. The flickering optics were becoming dimmer and dimmer. Cute. Especially with the transfluid smeared all over his faceplates. 

Magnus sighed and held Sentinel closer to him, stroking his back as the younger bot fell into recharge. He would be merciful...

...for now. 

Unsubspacing a cleaning rag, Ultra Magnus was smiling at the thought of Sentinel trying to stay awake; sleepily licking up the mess of lubricant and transfluid. That mental image was enough to pacify Magnus because he knew that he would get to see it happen in reality soon enough.


	8. Chapter 8

**Notes for the Chapter:**

> Feel like crap. Migrane. Ughhrrhhhrrbh

This was likely going to become a routine. 

Go to work, do what little scraps of assignments that are assigned to him, give them to Ultra Magnus, open his panel, and cater to his commander's needs until the end of the work day before managing to clean the transfluid and lubricant on his chassis and stumble back to his berth feeling like he had just forged the Allspark. 

On the second solar cycle of work, Sentinel turned in his reports for that cycle early; much to Magnus' pleasure. He was ordered onto the other side of the desk and told to bend over it while spreading his legs wide. Ultra Magnus hasn't done anything since then, though, making the Prime nervous. Even with his panel closed, knowing that Magnus was behind him and having the older mech's optics fixated, glinting with depraved excitement on his lower half, Sentinel felt acutely vulnerable. 

"Open your panel and tilt your aft upwards a bit more. I want to see your port." 

The order wasn't unexpected, but still unnerving to the inexperienced Prime. Still, he did as he was told punctually. 

"Good, good. Stay still, now." Magnus' thumbs parted his outer folds wide apart, making Sentinel shiver. 

It was lewd, and Sentinel's port heated up exponentially in response. Here he was, bent over his commander's desk with his legs spread open as the older Autobot's servos played with his valve... Primus. It felt surreal to be in this situation. Not gently, but not roughly either, Magnus pinched an inner fold and tugged upon it with slight force, making Sentinel's fans click on. He repeated the action, this time drawing a sharp intake from the Prime. Suddenly, the servos were gone for a few nanokliks before they returned with something that felt unfamilliar to Sentinel being rubbed over the gap between both sides of his outer port mesh. It felt... plastic and cold? 

Sentinel began to try and look over his shoulder to discern the identity of the object before he was cut off by the commander. "Sentinel, keep your optics forward."

Magnus took the opportunity to turn the device on. The sudden buzz against his port opening had the Prime's vents gasping for air as the vibrator abruptly began to stimulate the outer node endings of his valve with ferocious intensity. 

"Si-i-ir!" The Prime keened as Magnus massaged the mesh folds of his valve with the vibrator. 

Ultra Magnus smirked, watching the younger mech squirm tirelessly on the desk's surface with amused interest. In his other servo there was a remote which had both a vibration control slider and something else, something special, he had added to the vibrator's function. Sliding the bead downwards, Magnus rubbed it over the exterior node in slow circles making Sentinel keen and buck back towards him. With a swift move of his thumb, he pressed the ivory-colored button below the slider. 

A sudden jolt of electricity made Sentinel gasp and jerk violently at the sudden sting of pain. As soon as it happened, though, it was gone. To Sentinel's astonishment, his frame was running hotter and more fluid gushed from his valve. 

"You like that, Sentinel?" Magnus didn't wait for a response, pressing the button again immediately after finishing. 

The second sting still hurt, but, oh Primus; it somehow was good, alongside the vibrations...? Another sting jolted Sentinel's exterior node, his vocalizer let out a shrill keen in response. Melting into the processor-numbing sensations, Sentinel relaxed his frame, unknowingly pushing his lower half into Magnus' servo. Chuckling softly, the Autobot Commander moved the bead back up to the entrance to Sentinel's port and pressed the bead inside with his index finger. 

"S-Sir..." Sentinel whimpered, turning his helm to the side so that the left side of his faceplates rested upon the tabletop, looking back and up at the Magnus. 

Catching his subordinate's gaze, Ultra Magnus stood up and draped himself over Sentinel's backstruts as he pushed the bead as deep as it could go inside of the Prime's valve. Sentinel felt the digit retract from inside of his port completely before returning to his external node and caressing it generously as Magnus wrapped his derma around the tip of his audial and sucked on it gently. Yet another sting followed, Sentinel moaning desperately. Oral lubricant escaped the corner of his derma, which was embarrassing as slag. Behind him, the younger Autobot felt something poke at his bared port insistently; obviously, Sentinel recognized, it was Magnus' spike. Wiggling his aft unconsciously, Sentinel muttered something unintelligible and bucked backwards. 

"Stop squirming, Sentinel." Ultra Magnus said no more than that, thrusting inside to the hilt with one fluid motion. 

"Sir-!" 

This time, the pace was far from leisurely. Magnus began thrusting in and out almost immediately after fully sheathing himself inside of the fluttery port. Crying out as Magnus fragged him roughly, Sentinel found himself overloading shamefully fast. In response, the old Autobot slammed inside with a brutal rhythm that left Sentinel screaming the word 'Sir' over and over again, optics flickering and neural net alight with the pure pleasure that overrided all cohesive thought. His next overload caught him by surprise, his vocalizer straining as Sentinel howled in release. Magnus grunted into the orange and ashen audial feeling the port flutter and then tighten around his cord; pushing himself inside as deep as he could, he let himself overload. The added sensation of white-hot fluid rushing so deep inside of him forced Sentinel into his fourth overload of the solar cycle. His pedes kicked out uselessly as each shock wave of his climax rolled through his neural net. 

Once finished, Magnus pulled out of Sentinel quickly, optics fixated upon the thick trickle of his fluid that followed. Next, he grabbed the remote and the cord of the vibrator, turning it off and pulling it out of the Prime's valve. More transfluid splattered over his desk as he did so. Magnus quickly subspaced that vibrator and unsubspaced several more, though larger vibrating toys. These didn't have the sting feature, but that was perfect for what the Autobot Commander had in mind. Unaware of what Ultra Magnus was doing, Sentinel began to try and get up, attempting to ignore how the sticky viscous transfluid leaked indecently from his bared port, making him feel... dirtied. 

Suddenly, Magnus' servo descended upon his aft, spanking him hard. 

"We're not done yet, you naughty little bot. Now, be good and hold yourself open for me."

Oh Primus, again?!


	9. Chapter 9

After managing to stumble home when Magnus (finally) let Sentinel leave, the Prime flung himself onto the berth and recharged. The next solar cycle was shaping up to be similar to the last; not much actual work to do, just... scraps. Magnus, Sentinel presumed, wouldn't be able to try and berth him over the course of three workcycles. 

... Would he?

Well, he hoped the older mech couldn't. Magnus was practically an online relic of vorns and vorns passed! Granted, he was obviously functioning better than most bots Sentinel's age, but, still, Ultra Magnus was an old Autobot. The solace provided from this projection spurred Sentinel into, once again, finishing his work early to report them to the Magnus. Holding the datapads close to his chassis, the young Prime tried to ignore the fact that his interfacing equipment was onlining itself detecting the apparent establishment of a routine. The door cycled open, and he shuffled inside to find Magnus' desk much emptier than it was the previous solar cycle. Strange, but he tried not to dwell on it, pausing to salute his commander. 

"Ah, Sentinel Prime. At ease," Magnus didn't sound the least bit tired, though his faceplates seemed to perpetually be formatted into a tired expression-- that is, unless he was... greatly enjoying himself. "I was waiting for you to arrive; today was quite dull in terms of workload. Did you notice this as well?" 

Innocent conversation! Perhaps Magnus really was tired? 

"Yes, Sir. Is it usually like this?"

"Not at all. On most days, time is limited and it even gets hectic sometimes. It is prudent that all of our time can be utilized effectively. Though we musn't burn ourselves out, Sentinel, because we cannot be caught in a situation where we can't be at the apex of our readiness to respond because we're too worn down by mundane responsibilities. Do you understand, Sentinel Prime?" 

"Yessir!" Sentinel exclaimed, though the advice honestly didn't resonate with the young bot. 

"I always like to take advantage of the time we do get to relax, such as the end of work cycles and breaks." Magnus' tone changed in moments; his optics narrowed as he looked upon Sentinel with what could only be described as predatory interest. 

The corners of Ultra Magnus' derma turned up, azure optics dimming ever so slightly. In its' chamber, Sentinel's spark throbbed in anticipation as the gravity of the ambient atmosphere belatedly registered in his processor. That grin was almost identical to the ones he's seen in the past 3 solar cycles. A grin that was always used right before... Sentinel bit his lower derma and pressed his legs together in reaction to the memories. Slag it... the Prime could feel his interface array perk up in interest. 

Magnus caught the change in demeanor almost instantaneously. Locking the door with a remote command, he gave his subordinate a decievingly disarming smile, already planning what to do with the younger Autobot this time. An idea surfaced in his processor; sitting back in his chair, he released his panel. The sound of Magnus' panel clicking open attracted Sentinel's optics. From where he sat, he couldn't see much of the spike, perhaps just the tip. Surprisingly, Sentinel wasn't ordered to the other side of the desk, making him nervous and his frame maybe more than a little eager for what was to come. 

"It's best to enjoy oneself while it's possible, or at least I think so." Magnus purred, keeping optic contact with Sentinel. 

The Prime tensed, his chassis heating up faster and faster in anticipatory restlessness. To his absolute embarrassment, lubricant seeped out from the seams of his closed panel and pooled on the seat. Faceplates burning up with shame, Sentinel began to tremble due to a potent mixture of humiliation and excitement building in his spark. Magnus leered at the display, his spike stiffening further. How cute, Sentinel was getting himself so worked up. Something anamolous registered on the older Autobot's scanners; curiously, Magnus analyzed the readings from the scanner's data. 

Lubricant. 

The poor little thing was so excited that Sentinel couldn't seem to keep his array in check, it seemed. Hmm, the fact that his sensors was able to identify the lubricant from here meant that the chair was getting quite messy. Quickly revising his first idea to account for this development, Magnus smiled brightly at his subordinate. 

"Sentinel, it seems you're getting my visitor chair all wet with your leaking panel." 

Making a sound somewhere between a moan and a squeak, Sentinel stuttered out an apology, looking anywhere else than at his Commander. 

"Well? Let me see the mess you've made."

Sentinel's spark throbbed acutely in its' casing. He squirmed awkwardly, biting his lower derma. Slowly, very slowly, he moved his legs apart and to the side, revealing the wetness that accumulated beneath him. Magnus' engine rumbled pleasantly at the sight of his subordinate leaking all over both himself and the seat. 

"You've managed to soak the chair, I see. Hm, but your panel must be uncomfortable with all of that lubricant. Open up, Sentinel Prime." 

"Sir?!" Sentinel managed to look scandalized but his mien was obviously, embarrassingly eager as he gaped at his commander. 

"That was an order." 

Swallowing his fear, the Prime did as he was told. His panel snapped aside to reveal a gush of lubricant from his port and his spike; which pressurized so quickly that it was a little bit painful. The blunt tip of the short orange and blue spike was leaking transfluid as well. Magnus took his own cord in his servo, pumping a couple times to take the edge off of his excitement. Drawn to the movement, Sentinel's optics focused intently upon his superior's servo. 

"You're such a messy little thing, aren't you?" Ultra Magnus asked softly, his voice benign. 

Truthfully, Sentinel wasn't! Well, if you didn't count his interface array, that is. The seat was slick with valve lubricant, making the Prime shiver with a little bit of disgust. 

"I asked you a question, Sentinel Prime." Sentinel stiffened in momentary surprise before once again trying to sink into the chair due to being utterly humiliated. 

"Well, Sir, I'm not usually so m--" 

"Hush, Sentinel. A simple 'yes, Sir' or 'no, Sir' will suffice." 

Pausing for a moment, Sentinel nodded. But, what was he to say?! He could only say 'yes' or 'no'; without the clearance to say 'sometimes', Sentinel didn't want to risk saying it. Relenting, the Prime wriggled in place as he bit his derma. 

With a magenta-hued glow to his faceplates Sentinel looked up at Ultra Magnus and managed to force coherent words from his vocalizer. "Yes, Sir..."

The commander sat back in the large chair with servos folded over his midsection gracefully. It was excellent that Sentinel caught on so quickly to this game, and with such an excitable little frame, Magnus found himself immensely enjoying his new underling's presence... quite throughly. There were a multitude of 'things' that the Autobot Commander wanted to do with Sentinel, and almost as many other 'things' he would enjoy Sentinel doing for him. 

With just a little bit of guidance, and a touch more discipline, Sentinel was shaping up to be his second-in-command for a long, long time.


	10. Chapter 10

**Summary for the Chapter:**

> Yo sorry for the late update. Work's been piled on me at my job, along with IMMENSE STRESS that pretty much has to do with a lot of things happening right after the last chapter was posted, but I'm back now.

"You'll clean up the chair once we are finished, understood?" 

"Yessir." 

Magnus nodded and turned his attention to Sentinel's frame, making more energon tint the Prime's grey faceplates. 

"Sentinel," Magnus' voice was almost airy as he smiled again at his Sub-Commander. "I want to watch you self-service... would you, for me?" 

Sputtering, Sentinel's frame twitched almost violently in surprise. Then a whole new brand of embarrassment set in, burning up in his spark and making his whole chassis grow warmer. He hadn't ever touched his valve before! What was he supposed to do? 

Magnus watched the younger Autobot react with amusement. 

Certainly a prideful mech. Magnus mused that he'd like to one day get Sentinel to the point of begging shamelessly; which, judging from the Prime's character, would take a good amount of time and a lot more fragging. 

"I take it you've never touched your valve that way? It's alright, Sentinel Prime. You can start by touching your spike." 

The Prime's posture deflated a little bit in relief at Magnus' words. He nodded and opened his panel, though his hand hesitated for a moment before he began to timidly rub at the corners of his spike housing. Magnus' optics flicked from his face to his servo every once in a while. The attention was... it made Sentinel feel odd. He'd never thought about self-servicing for another 'bot to watch, and, the reality was surprisingly lavicious. A twitch from his steadily-pressurizing spike seemed to concur. He tried to ignore how indecent it felt to be self-servicing in front of someone and pretend he was in his quarters, or somewhere else. Just... not in public. 

His spike was pressurized now, but Sentinel's joints felt stiff and he was running hot. It must have been obvious how embarrassed he was, because Magnus chuckled in good humor at what must be an awkward scene. 

"I take it you don't self-service often?" Magnus asked, deceptively pretending to be bewildered. 

It took a moment for Sentinel to choke out the words, but he managed to answer regardless. "...Yes, Sir..." 

In this context, it was kind of embarrassing that he didn't do as much of what a lot mechs his age did in overabundance, though. Maybe he should try to self-service more...? But he doubted that anyone else would ask him to self service in front of them. Then again, Magnus may very well order him to do this a second time. He shuddered in apprehension. 

After a few more kliks, Magnus hummed thoughtfully. "Sentinel, come here and sit on my desk facing me." It wasn't a request...

Letting go of his spike, the Prime stood and creeped towards the desk warily, glancing at Magnus once in a while. He lifted himself onto the cold steel surface, the feel of it sending flashes of his first encounter with the Magnus through his mind. Ultra, for his part, seemed nonplussed about Sentinel's demeanor and was intently looking at his array. 

"You've never even touched your valve before?" Magnus asked, suddenly reaching forward to run his fingers over the damp entrance. 

"Only when washing, Sir." And it certainly felt weird! 

The CO hummed thoughtfully, the fingers shallowly slipping inside, making Sentinel shudder. 

"How about I show you, then?" A little smirk appeared on Magnus' faceplates. 

"Sh-show me...?" Sentinel was caught off guard by the question and even the way it was said when Magnus stuck two of his digits deep inside Sentinel. 

A cut-off whine escaped the Prime as he keened at the sudden intrusion. Those fingers were large compared to his own, and he'd be slagged if it didn't feel great. Not that he was admitting anything, of course. 

"Pay attention, Sentinel." 

The Prime hadn't realized he had shuttered his optics but quickly did as he was told... as well as he could, anyway. Once Magnus had been satisfied that Sentinel was now watching his servo, he quickly put pressure on the valve walls just below his digits and slid them downward in a sluggish manner. Immediately Sentinel's frame jolted and the valve reacted by clamping down onto the digits. It was hard for him to focus on Ultra's servo due to all the feedback, but Sentinel just barely managed to keep some attention on Magnus' "demonstration". 

Ultra's engines purred at the sight of Sentinel's writhing, and Magnus couldn't keep himself from rubbing the tender walls just a little bit to tease the cute mech on his desk. He then began playing with the elasticity of the walls, stretching them one way for awhile before going another way. Soon, Sentinel was practically weeping, and there was a small puddle of lubricant where he sat. Magnus merely smiled at Sentinel before suddenly beginning to thrust them in and out, sometimes pausing to rub the valve walls or exterior node.

Sentinel threw back his helm and sobbed through an overload, his own warm transfluid splattering over his upper torso. The squelching sounds coming from his valve's lubricants were ringing in his audials and it was getting harder and harder to think. It seemed Ultra Magnus was still "showing" him how to self-service with his valve, as he could feel the fingers twist a little and hook inside him and it was... just so embarrassing: he was already close to a second overload. Magnus being able to bring him to sobbing and squirming with only a small amount of effort didn't help his ego. It only took a couple more kliks before Sentinel whined as he came messily around Magnus' fingers. 

The digits stilled and pulled out completely, and Sentinel could hear Magnus' panel opening. 

"I hope you were paying attention. Now, let's see you try and get yourself to overload." 

"Wait, what...?" Sentinel asked with a small voice. 

Ultra smiled benignly. "Finger yourself, Sentinel Prime."

And that was an explicit order. Between the overload's afterglow and the sudden command Sentinel stalled and looked at Ultra Magnus with bleary optics, processing the situation. After a cycle of this, Magnus tapped his fingers against the chair's armrest noisily, if only to hurry Sentinel along. The Prime's fingers moved to occupy the space Magnus' fingers did, though hesitating to go inside. With a deep breath Sentinel pushed the first one inside, the depth and girth nothing like his commander's digits. 

It took Sentinel a moment to work up the courage to keep going, but with Ultra's stoic optics watching him Sentinel forced himself to start moving his finger. His wet mesh walls flexed around him, coating the digit in lubricant. 

"Two fingers. You just took two of mine, so yours should fit easily now." Magnus spoke, his voice so monotone if this were any other situation Sentinel wouldn't think twice. 

However he was a good Autobot, and he followed his Magnus' orders. 

Hastily thrusting another finger inside left him keening in pain from the sudden stretch, and he paused a moment to once again get used to it. Curse his large servos! As soon as he felt the sting subsiding the Prime began shallowly thrusting the two fingers in and out, vents panting from the sensation. It was obvious, Sentinel managed to observe, that he was unpracticed at... fingering a valve... compared to Ultra. Ultra would have already had him squirming. A faint flush colored his cheeks at the thought. 

There was a sigh, followed by servos grabbing his own and pinning him to the desk. Before Sentinel Prime could begin to process what was happening the large form of the Magnus was hovering over his prone chassis. 

"Sir?" Hiccuping in terror, Sentinel fought the urge to thrash. 

"You need practice. Promise me you will, Sentinel?" 

"I, uh--" 

Magnus was already kissing him and roughly pulling his legs even wider apart, a certain spike already nudging between his valve folds. The only warning he had was Magnus pulling away and smiling with an odd edge to it before Ultra's spike was thrust in all the way to the hilt in a single push. Predictably, Sentinel threw back his helm and screamed. It hurt and felt good and he couldn't think like this, his servos denting Ultra's forarms. No time was given to recover as the thrusts following came in rapid succession, bouncing the Prime up and down on the desk. Tears welled up as quick as the lubricant came out of his valve with each thrust. Soon, Sentinel was lost to the sensation of almost all his nodes being pounded into over and over again. 

"Look at me." 

Sentinel did as he was told, turning his gaze from nothing to Ultra's face, which he still couldn't read, even now. Nanokliks later the thrusts came much harder than they'd ever been and were aimed right towards the nodes at the back of the valve. With a loud yowl Sentinel overloaded right there. A burst of lubricant squeezed out around Ultra's spike, which was now thrusting with no rhythm. In a haze, Sentinel again looked at Magnus, mouth agape and cleaner fluid staining his energon-flushed cheeks. Magnus' vents hitched and he thrust in deep and held himself there, the warmth of his release flooding Sentinel's valve completely. Spent, Magnus pulled out and a small gush of transfluid followed. Sentinel had his optics offline, laying motionless on the desk. 

"Clean yourself off, and then you are dismissed." Ultra's voice was even, as if he hadn't just pounded into his subordinate officer. 

Sitting up, Sentinel winced with a throb of pain from his valve. He had washed the cleaning rag since last time it saw use, thankfully. 

"Sentinel." 

"Yes sir?" Sentinel's voice came out much more winded than he had hoped. 

"I meant it when I told you to practice." Ultra sat back in his chair, picking up a datapad to the left of where Sentinel sat. 

"I- um, Sir, I... yes Sir." 

Magnus hummed, looking at Sentinel again. 

He intended to teach Sentinel to self-service better for him to watch, indeed. But Sentinel also needed to be acquainted with... other things first, as well.


End file.
